Hi Alan,
> I concur with your approach.
>
> My 'classic' spinner has been a constant irritation over the years. I've
> never tried to have it dynamically
> balanced, due cost.
> It is now within acceptable limits throughout the entire rev. range.
(though
> there are rev. ranges where it
> can be detected)
Using Grahams carbon fibre bulk head and back plate helps stop the spinner
going into a fit of the wobbles and exaggerating the problem.
> I achieved this by following the approach that you have described.
> Basically, there are three potential
> sites for washers
Using the outer six screws gives even more fine adjustment, washers can be
place either side of the offending blade, or nearer the heavy part of the
spinner.
> and with each flight I repositioned them.
I found a static run up was all I needed. In flight conditions produced the
same results.
> When I achieved
> a result with lower vibration,
> I varied the weight of the load. (NB. take care the screw threads are long
> enough as the prop is vulnerable
> in this area).
> The other thing to bear in mind is that not all classic spinners are the
> same. One of mine was too out
> of balance to correct. This can be because it is mis-shapen, or because of
> variable weight distribution
> as a result of the manufacturing process.
> My cone was carefully rubbed down and balanced as much as possible before
> attempting final adjustment
> on the aircraft.
> I often wonder if the result would have been better, if I had spent the
> money and had it done professionally.
The only way to find out is to have it done, but in my case it was a
complete waste of time and money.
Jim
|